Gear-cutting machine



Aug. 112; 1924.

L5472 C. A. PARSONS ET AL GEAR CUTTING MACHINE Filed June '7, 1923v 2 Sheets-Sheet l 2 Willi/111m ma@ n2 1924.. www2 C. A. PARSONS ET AL GEAR CUTTING MACHINE Filed Jne 7, 1923 2 Sheets-Sheet 2 @E Mmm n Ireland,

Patented Aug., l2, 11924,

CHARLES ALGERNON PARSONS AND STANLEY SMITH COOK, O'l NEWCSTLE-ONTYNE,

ENGLAND; SAID COOK ASSIGNOR TO SAID PARSONS.

GEAR-CUTTING MACHINE.

Application filed .Tune 7, 1923.

T0 all 'whom t may concern.'

Be it known that we, CHARLES ALGERNON PARSONS and STANLEY SMITH Coon, both subjects of the King of Great VBritain and and both residing at Heaton Works, Newcastle-on-Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in and Relating to Gear-Cutting Machines, of which the following is a specification.

The invention relates to gear-cutting machines of the type in which a creeping mo tion of the table supporting the workis provided in order to distribute errors due to inaccuracies in the main or other gear wheel of the train driving said table.

In order to. explain the object of the present invention, reference is made herewith by way of example to theftype. of creep gear-cutting machine described m United States specification No. 1,234,379 dated the 241th day-of July, 1917, in which the phasechanging gearV train is carried by what is therein called the primary table, while the work itself is carried by the secondary table.

In the gear-cutting machine described in that specification it will be seen that in consequence of the continuous variation of the point of engagement in relation to the work and in relation to the cutter the direction of the force which serves torotate the secondary or work-oarrying table continuously changes and since there must be a running clearance between the journal and bearing which centre the work-table, a slighteccentric movement of the latter may take place in such a way-that `the axis of the table moves round in a small circle and thereby effects the accuracy of the finished wheel.`

The object of the present invention is to prevent the occurrence of such a movement `*and thereby to eliminate a possible source of error in the finished wheel.

With this object, the invention consists in thel combinations of elements hereinafter set forth and more particularly pointed out in the claims.

Referring to the accompanying drawings, which illustrate one form ofthe invention by way of example Figure 1 `shows a cross-sectional elevation through the creep-producing drive;

Serial No. 644,016.

Figure 2 being a plan with the workcarrying table removed, and

Figure 3 asection on the line 3*-3 of Figure 1.

In carrying the invention into effect according to the 4form shown in the drawings, the gear train may be substantially of the type shown in Figures 1 and 2 of patent specification No. 1,234,379 of 1917. Thus, the primary member, 0 is formed as a worm-wheel and driven by a worin, rotatably mounted on the frame, c, and itself carries a pinion, d, gearing with a stationary spur or helical sun wheel, c, and so acting as the planet of a sun and planet gear. The planet is integral with a mitre wheel, y, gearing with a companion, 7L, mounted on a spindle, 7c, carrying a worm, m, which gears with a worm-wheel, a, attached to the secondary member or work-carrying table,

' All the members of the creep-producing train between the stationary sun wheel, c, and the worm-wheel, a, on the secondary member are mounted on the primary member, a, and rotate with it.

According to the present invention, in order to compensate for the unsymmetrical action of the creep-producing gearcarried round on the primary member, a, a second similar creep-producing gear is introduced at a point diametrically opposite, the elements of this gear being indicated in the drawings by accented reference symbols. rIhe worm spindles, fc, are, however, splined (see fr', Figures 1 and 2) respectively to their coaxial mitre wheels, 7i, 7L', the latter being prevented by suitable collars, a, s', from axial movement in their bearing brackets, t, t', while on the other hand the worm spindles, 7c, 7c', are capable of moving axially in the second bearing bracket, u, a', provided in each case, so that the relative configuration of the spindles, In, 7c', and the sun wheel, c, is varied.

In order to ensure an exaotvbalancing of the drive, the two worm spindles, la, c, are interconnected by any suitable form of differential or balancing gear.

According to one such form, a lever formed of upper and lower plates, fu, o, is

rotatably mounted on the'stud or pin, fw,

forming a fulcrum and carried by the primar-y member, a, the plates, o, o, at one end engaging with a pin,` a, forming part of the thrust washer, 2, disposed between the thrust collars, 3, 4, on the worm spindle, 7.1. Asecond lever, formed of upper and lower plates, o, o, similarly mounted, eoacts with the second worm spindle, c, the two levers being interconnected at their other ends, as shown, by a linlrformed of upper and lower plates, 5, 5, passinground the centre spmdle, 6, of the work-table, o.

By means of the interconnection described, the thrusts of the worm spindles, fr, and 7c', are equalized and a pure couple drive thereby transmitted to the work-carrying table.

The creep-producing drive is thus transmitted to the work-table, 0, in parallel through the two sets-of gearing, the interconnecting mechanism serving to correlate the longitudinal positions of the worm spindles, 7c, lo", in their bearings.

rIhe remaining forces acting on the workcarrying table, mainly frictional resistance to rotation, forces produced by the toothcutter and the weight of the table itself and. its adjuncts, are. constant in direction and substantially constantl in amount, so that the resultant of all the forces acting on the work-table is itself substantially constant and the centring journal retains a constant position in its retaining bearing during the cutting operation.

It will be seen that instead of the interconnecting linlrs described, any other suitable form of differential or balancing gear may be utilized for the purpose.

In addition, the scope of the invention is broad enough to include any suitable alternative form of the main gear train.

Having now described our invention,

what we claim as new and desire to secure by Letters Patent is l. In ya gear-cutting machine of the creep type, the combination of a plurality of creep-producing gear trains in parallel, together with means for equalizing the action of said trains, as set forth.

2. In a gear-cutting machine of the creep type, the combination of a plurality of epcyclic creep-producing gear trains, said trains including `|a common sun, together with means for equalizing the action of said trains, as set forth.

3. In a gear-cutting machine of the creep type, the combination of a prim-ary gear, a secondary'or work-carrying gear, a plurality of creep-producing gear trains in parallel between said gea-rs, together with means for equalizing the action of said trains, as set forth.

t. In a gear-cutting machine of the creep type, the combination of a primary gear,

, a secondary or work-carrying gear, a plurality of creep-producing gear trains mounted on one of said gears and gearing with the other, a third gear co-axial with one of said gears and gearing with said plurality of trains, 4together with means for equalizing the action of said trains, as set forth.

5. In a gear-cutting machine of the creep type, the combination of a. primary gear, a secondary or work-carrying gear, a plurality of creep-producing gear trains mounted on one of said gears and gearing with the other, a third gear co-axial with one of said gears and gearing with said plurality of trains, said third gear and certain corresponding members of said trains being relatively movable to change their configuration, asset forth.

6. In a gear-cutting machine of the creep type, the combination of a primary gear, a secondary or work-carrying gear, a plurality of creep-producing gear trains in parallel between said gears, said trains including gear elements axially movable together with means for correlating the axial positions of said elements, as set forth.

7. In a gear-cutting machine of the creep type, the combination of a primary gear, a secondary or work-carrying gear co-axial therewith, a pair of like creep-producing gear trains in parallel between said gears and arranged diametrically opposite in relation to the common axes of said primary and secondary gears, together with means for equalizing the action of said trains, as set forth.

S. In a. gear-cutting machine of the creep type, the combination of a primary gear, a secondary or work-carrying gear, a plurality of creep-producing gear trains mounted on one of said gears and gearing with the other, a third gear eo-'axial with one of said gears and gearing with said plurality of trains together with means for equalizing the action of said trains, said equalizing means including elements mounted on the same gear as are said trains, as set forth.

9. In a gear-cutting machine of the kind indicated, the combination of a primary gear, a secondary or work-carrying gear, a pair of creep-producing gear trains mounted on said primary gear and gearing with said secondary gear, a third gear coaxial with said primary gear and gearing with said pair of trains, together with means for equalizing the action of said trains, as set forth.

l0. In a gear-cutting machine of the kind indicated, the combination of a primary gear, a secondary or werk-carrying gear, a pair of creep-producing gear trains mounted on said primary gear and gearing with said secondary gear, a third gear coaxial with said primary gear and gearing with said pair of trains, said third gear and certain corresponding members of said trains being relatively movable to change their configuration, as set forth.

l1. In a gear-Cutting machine of the kind 5 indicated, the combination of a primary gear, a secondary or Work-oarrying gear, a pair of Creep-producing gear trains mounted on said primary gear and gearing with said seoondary gear, a third gear coaxial with said primary gear and gearing With said pair of trains together with means for equalizing the l.action of said trains, said equalizing means including elements mounted on the primary gear, as set forth. In testimony whereof We have signed our names to this specification. l CHARLES ALGERNON PARSONS.

STANLEY SMITH (300K. 

